Speech recognition system and method using group call statistics

ABSTRACT

An enhanced speech recognition system and method are provided that may be used with a voice recognition wireless communication system. The enhanced speech recognition system and method take advantage of group to group calling statistics to improve the recognition of names by the speech recognition system.

PRIORITY CLAIMS/RELATED PATENT APPLICATIONS

This application claims priority under 35 USC 120 to and is acontinuation of U.S. patent application Ser. No. 13/029,954 filed onFeb. 17, 2011 and entitled “Speed Recognition System and Method UsingGroup Call Statistics” (to be issued as U.S. Pat. No. 8,498,865 on Jul.30, 2013) which in turn claims priority under 35 USC 120 and is acontinuation in part of U.S. patent application Ser. No. 12/253,898,filed on Oct. 17, 2008 and entitled “System and Method for ImprovingRecognition Accuracy in Speech Recognition Applications” (issued as U.S.Pat. No. 8,175,887 on May 8, 2012) and U.S. patent application Ser. No.11/000,590 filed on Nov. 30, 2004 and entitled “System and Method forImproving Recognition Accuracy in Speech Recognition Applications” (nowU.S. Pat. No. 7,457,751).

FIELD

The disclosure relates generally to a system and method for correctlydistinguishing among multiple possible interpretations of utterances inspeech recognition applications. In particular, this disclosure relatesto a system and method for distinguishing among multiple possibleinterpretations of utterances by the speech recognition unit of acommunications system.

BACKGROUND

Speech recognition systems are well known technologies today. A speechrecognition system is used, for example, in telephone automated responsesystems, communication system and other systems in which it is desirableto be able to have a computer system recognize speech and commands froma human being and then act on those commands. An example of acommercially sold speech recognition system is sold by NuanceCommunications, Inc.

One problem that exists in speech recognition systems is scalability. Inparticular, when a speech recognition system is scaled in size, thenumber of user names in the speech recognition database becomes verylarge. As a result, it becomes more difficult for the speech recognitionsystem to correctly recognize a user name. As a result, the userexperience with the speech recognition system can be frustrating or thespeech recognition system can fail to corrected identify a user based ona voice command.

In some applications of speech recognition that require calling, thefrequency of calls made by a given person to other persons isnon-uniform; i.e., some users are called by a given user with greaterprobability than others. In certain contexts, the patterns of callingmay satisfy the following two properties.

-   -   The locality property of a speech recognition system, which        means that a person in a particular group (or department) tends        to call people in a limited set of other groups (or        departments).    -   The substitutability property of a speech recognition system,        which means that a person in a particular group tends to call        the same other groups as other people who are in the same        particular group.

These properties can be harnessed to overcome the scalability problemwith speech recognition system and it is desirable to provide a speechrecognition system and method that harnesses these properties and it isto this end that the disclosure is directed.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 depicts an example of a voice-controlled wireless communicationssystem that may utilize a speech recognition system;

FIG. 2 is a block diagram of an exemplary controlling computer (VS) ofthe voice-controlled wireless communications system;

FIG. 3 is a block diagram of the application software component of thecontrolling computer shown in FIG. 2;

FIGS. 4A-4H and 4J-4Y illustrates different embodiments of a badgedevice that can be used with the voice-controlled wirelesscommunications system;

FIG. 4Z illustrates an access device having a badge application for usewith the voice-controlled wireless communications system;

FIG. 5 illustrates more details of the voice command interpreter thatmay include a group unit;

FIG. 6 illustrates a method for speech recognition using group calling;

FIG. 7 illustrates an example of calling statistics that may be used bythe speech recognition method;

FIG. 8 illustrates a department assignment user interface of thevoice-controlled wireless communications system of FIG. 1 when used in ahealth care industry;

FIG. 9 illustrates a group/department selection user interface of thevoice-controlled wireless communications system of FIG. 1; and

FIG. 10 illustrates a data check user interface of the voice-controlledwireless communications system of FIG. 1.

DETAILED DESCRIPTION OF ONE OR MORE EMBODIMENTS

The disclosure is particularly applicable to a voice controlled wirelesscommunication system that uses speech recognition as described below andit is in this context that the disclosure will be described. It will beappreciated, however, that the system and method for speech recognitionusing group call statistics has greater utility since the system andmethod disclosed below may be used with any system that incorporates aspeech recognition system in which it is desirable to increase thespeech recognition accuracy of the system. In addition, although thesystem below is described in a health care installation, the system andmethod for speech recognition using group call statistics also may beused in other industries in which group calling patterns exist and canbe used to improve the speech recognition and is thus not limited to theexemplary health care industry.

FIG. 1 depicts an example of a voice-controlled wireless communicationssystem 30 that may utilize a speech recognition system. The systemcomprises a plurality of wireless communication devices or accessdevices referred to as Badges 32 below (marked B1-B5 in this example),one or more concentrators 34 (marked AP), such as wireless access pointsfor example, and one or more central computers referred to ascontrolling computers 36 (marked VS), as shown. The concentrators 34 inFIG. 1 may be standard off-the-shelf wireless access points, such as astandard 802.11 access point in one embodiment, which collectivelyimplement a wireless network allowing the Badges 32 to communicate withother components of the communications system 30. The concentrators 34communicate with each other, and with the controlling computer 36, overa computer network 38 which may be a local area Ethernet network in oneembodiment. Taken together, the concentrators 34 and the computernetwork 38 provide the network infrastructure for the wirelesscommunications system 30. Any of the controlling computers 36 may alsobe interfaced to a telephone system such as a Private Branch Exchange(PBX) system 39, which allows the wireless communications system 30 tocommunicate with common telephone communication systems. Each Badge 32is a wireless communications device that is capable of communicatingwith a concentrator 34, and therefore is also capable of communicatingwith the controlling computer 36 in order to implement the desiredwireless communication functions. Each Badge 32 serves as one of theprimary communications endpoints of the system.

FIG. 2 is a block diagram of an exemplary controlling computer (VS) 36of the voice-controlled wireless communications system. The controllingcomputer 36 is responsible for the overall control of the system. In oneembodiment, the controlling computer 36 may be a typical off-the-shelfcomputer system, such as a typical server computer, the hardware detailsof which are well known. In more detail, the central computer 36 mayinclude a central processing unit (CPU) 124 and a persistent storagedevice 128, such as a hard disk drive, an optical drive, a flash memoryor the like. The controlling computer may also have telephony interfacehardware 134 that permits the controlling computer to interface to atelephone and/or Public Branch Exchange (PBX) system 39, and a computernetwork interface 132, such as the Ethernet interface shown, thatpermits the controlling computer to connect to the computer network. Inaddition, the controlling computer 36 must have a memory 126 that storessoftware currently being executed by the CPU 124. This software includesat a minimum an operating system 122, application software 120 toimplement the wireless communication functions of the wirelesscommunications system, and a database 130 to store informationassociated with the wireless communications system. This databaseinformation includes but is not limited to a grammar database 260 thatis part of the system into which name information, group callingstatistics for different groups of users, probabilities that aredetermined for users of a particular group based on the group callingstatistics for the particular group and the modified grammar as a resultof the probabilities from the system and method that are stored asdescribed below in more detail.

The database 130 stores user information, including the assignment ofusers to devices, speech files containing user name prompts and voicesignatures, user preferences and so forth. It also keeps track of thewhereabouts of users as they roam within the communications network. Inlarge corporate installations, this component may interface to globalemployee databases maintained by the customer. Some information fieldsin database 130, for each user of the system, may include but are notlimited to the following: user name, login name, password, alternativename/identifier, phone number and address, voicemail greeting message,ring tone, caller identifier status (on/off), buddy list, block list ofcalls to block, message forwarding service status (on/off and if on, towhat number), distribution groups (e.g. “Memory Marketing Team”), savedmessages, and device serial number.

FIG. 3 is a block diagram of the application software component 120 ofthe controlling computer shown in FIG. 2. In one embodiment, theapplication software comprising one or more portions of code whereineach portion of the code has a plurality of lines of computerinstructions that implement the operations and functions describedbelow. The software may include a voice command interpreter 140, a callmanager 142, a connection manager 144, and an administrator 146 that areinterconnected together and exchange commands and data with each otheras shown. The voice command interpreter 140 has responsibility forinterpreting and executing voice-based commands received from theBadges. The call manager 142 has responsibility for the set-up and thebreakdown of two-party and multi-party calls (including external calls)and maintaining status information associated with these calls. Theconnection manager 144 is the component that is responsible for managingaccess points and the connections among Badges and access points. Italso supports a hand-off from one access point to another as a Badgeroams about the network. The administrator module 146 supportsadministrator-level and user-level configuration and monitoring of thesystem through a web browser interface as shown. The administrator userinterfaces for the group calling functionality is described below withreference to FIGS. 8-10.

As an example of the use of the system above, suppose a person wearing aBadge wants to speak to Maria Bettini, who is also wearing a Badge. Theperson initiating the communication presses a button on the Badge,receives an audible prompt, and then utters the command “Call MariaBettini.” The Badge digitizes this utterance and transmits it as datapackets over the wireless network to the controlling computer. A speechrecognition engine in the controlling computer (described in more detailwith reference to FIG. 5) associates the argument in the command (MariaBettini) with a user in the configuration database, and the controllingcomputer then establishes communication between the Badge of the personwho initiated the call and Maria Bettini's Badge. After establishing thecommunication session, the controlling computer drops out of theprocess, the two Badges communicate directly with each other over thewireless net, and no additional speech recognition is performed.

In one embodiment, a person wearing the Badge can utter a command thatcomprises a verb and an argument. The verb specifies the action that theperson initiating the communication wants to perform with the Badge.Examples of verbs include “Call,” “Send a message to,” and “Broadcastto.” The system defines a static set of verbs; that is, the availableverbs are the same at every customer installation. The argumentspecifies the name of a Badge user (such as “Maria Bettini”), a group ofBadge users (such as “Fifth Floor Nurses”), or an address book entry (aperson or place that does not have a Badge, but whose name and phonenumber are entered in the customer configuration database, such as“Poison Control”). The set of possible arguments is specified in thecustomer configuration database and is dynamic—that is, the databaseentries differ at every customer installation, and users at customerinstallations can add and remove database entries continually. Becausethe set of arguments contains not just Badge users but also groups ofBadge users and outside entities, the number of possible arguments canbe quite large. Together, the entire set of words and phrases the systemcan recognize—the set of verbs and arguments—composes the recognitionspace.

FIGS. 4A-4H and 4J-4Y illustrates different embodiments of a badgedevice 32 that can be used with the voice-controlled wirelesscommunications system and FIG. 4Z is an access device having a badgeapplication for use with the voice-controlled wireless communicationssystem. Before describing the details of the different embodiments ofthe badge, a general overview of the badge and its operation will beprovided. The badge of the first two embodiments (shown in FIGS. 4A-4Hand 4J-4Y) is a portable, battery-powered, lightweight, wireless devicethat serves as the primary communications endpoints of the system. Thebadges support hands-free, near full duplex voice communications using asmall microphone (situated near the top of the badge as described below)and a speaker (located near the bottom of the badge as described below)or the microphone and speaker of the access device. In addition to thewireless communications, each badge is preferably capable of receivingtext pages or from an e-mail client in the server 36 or from a browserapplication hosted on the server 36 and may include a display unit (asdescribed below) to, among other things, permit reading of the textpages.

Each badge is only capable of voice communications when it is within thenetwork neighborhood of any concentrator. The typical range of aconcentrator is approximately 35 meters for an indoor concentrator andapproximately 100 meters for an outdoor concentrator. Thus, when thebadge is not within the range of any concentrator, voice commands do notwork. When the badge is an access device with the badge application, thecoverage may be by a plurality of cellular base stations with a cellcoverage area of about 5 miles. When the access device are wired phoneswith network switch concentrators, each network switch has aconnectivity area which is the area over which wired phones areconnected to a particular network switch.

The badges of the first two embodiments are sufficiently small andlightweight enough so that the badge may be clipped onto a shirt pocketof the user, may be worn on a lanyard around the neck of a user orcarried is a holster similar to cellular phone. In a typical environmentwith typical noise levels, hands-free operation using voice commandsrequires the badge to be situated approximately 0.5 meters from themouth of the user so that the voice commands may be understood by thecentral computer. Thus, if the badge is carried in a holster, it mayneed to be removed from the holster and brought closer to the user'smouth for voice command, hands-free operation. For a semi-privateconversation or operation in a loud environment with high noise levels,the badge may be inverted (so that the speaker is near the user's earand the microphone is near the user's mouth) similar to a typicaltelephone. Optionally, a headphone jack may be provided on the badge.The badge may also include a clip (as described below) that may be usedto clip the badge onto a shirt or shirt pocket or may be used to hold acorporate security badge.

The badges may be powered by a renewable energy source, such as areplaceable, rechargeable lithium polymer or lithium ion battery, thatattaches to the back of the badge. The battery may be needed to berecharged each day for voice operation, but it may last longer if thebadge is used for only text functions. The invention, however, is notlimited to any particular energy source and any renewable ornon-renewable energy source may be used. The badge may include acharging adapter as an accessory for recharging the renewable energysource and the charging adapter may be a docking station or simply awall transformer.

The two embodiments of the badge shown in FIGS. 4A-4H and 4J-4Y mayinclude a wireless transceiver and an antennae (that may be a 100 mwBluetooth radio transceiver, an appropriate strength IEEE 802.11 (b) or(g) transceiver or any other wireless transceiver) that is used forwireless communications with the concentrators or with other badges asdescribed below. In one embodiment, each badge contains an 802.11 (b) or(g) transceiver capable of transmitting at approximately 20 dBm (100mW), and receiving with a sensitivity of approximately −85 dBm. Thebadges also contain a DSP engine and voice codec for speech processingand control, a display control processor and LCD display, a lithiumbattery with protection circuitry, an audio amplifier, microphone, andspeaker. Each badge is factory-assigned a unique physical (MAC) address.The antennae for the wireless transceiver, in one embodiment, may bebuilt into the clip of the badge or may reside completely within thebadge. Each badge is assigned a unique wireless device address (so thatit can be identified by each concentrator and the central computer.)

Each badge may further include a central processing unit (CPU) thatcontrols the operation of the badge and each of its components includingthe wireless transceiver. For example, the CPU may also control amicrophone and a speaker that are components of the badge and permit theuser of the badge to communicate with the central computer using voicecommands and receive voice responses from the central computer. Thebadge may further include a well known non-volatile memory chip (notshown) so that data stored in the badge (such as settings and messages)are not lost when the badge is powered down. For example, thenon-volatile memory device may be a well known flash memory device. Themicrophone and speaker may also be used for voice communications withother badge users or third parties. The badge may further include anamplifier 64 that amplifies the signals provided to/from the microphoneand speaker.

The badge 32 may also include a display device 66, such as a liquidcrystal display (LCD), that may be used for various purposes, such asreviewing text messages and pages received by the pager receiver, topermit the user to control the operation of the badge and itsconfiguration using a control menu or to announce the origin of anincoming call. In one embodiment, the display device 66 may be amonochrome dot-matrix display with approximately 32 rows and 60 columns.The display has sufficient resolution to permit four lines ofapproximately fourteen characters per line. In the preferred embodiment,the display device 66 may be situated on the back of the badge (as shownin FIG. 4C) to protect it from damage and so that it is not normallyvisible without flipping over the badge or removing it from its holster.As described above, the badge may include a renewable energy source,such as a removable, rechargeable batter as shown, that may includeprotection and charge management circuitry as is well known to preventover-charging. The badge may further comprise a digital signal processor(DSP) and an audio codec for processing incoming speech from themicrophone and for generating the voice signals generated by thespeaker. For example, the DSP and audio codec are capable of compressingthe digital voice data to reduce the amount of digital data used tocommunicate the voice commands to the server. The compression isperformed by a commercially available compression software sold byVoiceAge. The badge 32 may further include an input device 74 thatpermits the user to control the operation of the badge and itsconfiguration. In one embodiment, the input device may be a jog switchwhich is a spring-loaded compound-action switch that supports threemomentary actions. In particular, the switch may be pressed inwards asan ordinary push button. The switch may also be rotated in eitherdirection. The function of these actions depends on the context. Forexample, if a call is in progress, the up and down movements may controlvolume. When a call is not in progress, these movements may control menuand message scrolling in the display. Certain input operations mayrequire that the switch is pushed in for more than some predeterminedamount of time. In the following descriptions, it will be convenient tospeak of the jog control as if it were three separate buttons forclarity. Therefore, the inward push control will be called the activatebutton; the other two controls will be referred to as the scroll up andscroll down buttons. Many jog operations are carried out by pressing andreleasing almost immediately; we will say “press the activate button”,for example, to mean press and quickly release. A few operations requireholding for some predetermined period of time, such as at least half asecond, before releasing. We will say “press and hold” in this case.Thus, the user interacts with the system through a combination of thejog switch and voice controls. In one embodiment, the input device 74may be a touch button located in particular location, such as on thefront of the badge, that may be pushed or touched to activate the samefunctions and operations being activated by the jog switch.

The badge may also include an on/off switch 76 and a status indicator78. In one embodiment, the status indicator may include an LED that iscapable of displaying one or more different colors to signal theoperational status of the badge. For example, a slowly blinking greenlight indicates that the badge is within the network neighborhood and isoperational while a slowly blinking read light indicates that the badgeis not within a network neighborhood. The badge may further optionallyinclude a headset jack 80 that enables the user to plug in an externalmicrophone/speaker headset, such as an ear bud. When the externalheadset is plugged into the jack 80, the operation of the internalmicrophone and speaker is inhibited.

The wireless system must know which badge each user is wearing so thatcalls to the user can be properly routed. Badge assignment is theprocess of associating a badge with a particular user. The assignmentmay occur when a badge is first activated. At that time, the systemprompts the user to identify himself verbally. Depending on theinstallation, it may also be necessary for the user to say a passwordprovided to him by the administrator, or a voice signature that ismatched against a pre-recorded entry in the database of the server 36.Assuming the user is known to the system, the system will recognize thename, and will then (after a confirmation) assign the badge to the user.When the badge has been dynamically assigned to the user, the user'sprofile stored on the server 36 will be associated with the particularbadge so that, for example, the user's preferences are active or thealternate names of the user are known. Once assigned, the serial numberof the badge will show up on the user's console (as described in moredetail below), and the badge can display a welcome greeting, when turnedon, that is personalized to the user (e.g., “Hello, John”). The server36 may also store text messages that may be downloaded to the badge atthis time. A given badge can be assigned to at most one user at a time,and each user can be assigned only one badge at a time. A badge canlater be reassigned to another user, if desired, via a voice command.Alternatively, the system administrator can explicitly set the serialnumber of the badge to be assigned to a user through the user console. Abadge is not tightly bound to a single user as would be the case with atypical cellular phone, wireless e-mail device or other devices sincethe badge is dynamically bound to the user when the user uses the badge.As an example, when a badge is not being used by any particular user, itis not assigned to any user and is available for use by any user. Whenthe user is assigned to a badge, the user profile on the server isassociated with the badge. However, the user profile is not stored onthe badge since the badge is merely a device used to access the system.As an example, a company may have 50 badges which are available for use.In accordance with the invention, when a user needs a badge, such as atthe start of a workday, the user is assigned a badge (as describedbelow) and uses the badge. At the end of the day, the user returns thebadge to the charger station and the badge returns to an unassignedstate in which any user may pick up and be assigned to the badge.

The bearer of the badge must typically first be registered with thesystem (or be registered by the administrator) before the badge can beassigned to him. In cases where visitors may be provided with a badge tobe used temporarily, it may be useful for the administrator to registera few “Guest” users (the registration process only takes a moment) andassign guest badges to them. If desired, the spoken name of the guestcan be entered through the user console, so that other users can hailhim by name as opposed to, say, “Guest Three”. As noted above, theassignment process entails that the user speak his own name so that hemay be recognized by the system. The name will be recorded by the systemand used for constructing a confirmation prompt when other parties call(“Finding . . . John Smith”). If the spoken name of the user is laterchanged in the User Console, the user will be prompted to re-speak thename the next time his badge is successfully activated. The user issimilarly prompted to speak the identifying phrase (“John Smith inSales”) if one is provided. As shown in these two embodiments, the exactlocation of the various components on the badge may be varied withoutdeparting from the scope of the invention.

FIGS. 4J-4Y illustrate two other embodiments of the communications badge32. These embodiments of the badge have the same elements as the priorembodiments so those elements will not be described. The embodimentshown in FIGS. 4J-4Q has the clip 82 as shown while the embodiment shownin FIGS. 4R-4Y do not have the clip. Both of these embodiments do notinclude the jog switch, but have a different device. In the embodimentsshown, the display 66 may be a monochrome dot matrix with a grid size of32 rows by 60 columns. The grid is sufficient to display up to fourlines of approximately 14 text characters per line in a 5-point font.The display is situated at the back of the badge, and so is normally notviewable without some manipulation from its normal position. The displayis used to indicate badge status (such as battery charge, on-off networkstatus, and signal strength), to peruse text messages, to announce theorigin of incoming calls, and for various control menu functions. Inaddition to the elements of the other badges, these badges include aactivate button 87 and a do not disturb/hold button 88.

The activate button 87 is the primary control with which the userinteracts with the badge and is a momentary push button on the front ofthe badge as shown. This button is used to initiate a dialog with thesystem agent (the “Genie”), as well as for various call controlfunctions. The activate button supports two momentary actions; it mayeither be pressed and immediately released (a press), or pressed andheld down (a press-and-hold) for longer than a brief moment. The lengthof a “brief moment” will need to be determined through experiment, butis likely to be approximately 600 milliseconds. While the functions ofpress and press-and-hold depend on the context, the general rule is thata press is used for an affirmative action (such as initiating oraccepting a call). The press-and-hold is used to power down the badge.

The do not disturb/hold button 88 is a second momentary push button thatis provided at the top of the unit as shown to allow the user to placethe badge in a do-not-disturb (DND) mode (if no call is currently inprogress), or to put a call on hold (if one is in progress). The buttonacts as a simple toggle. This button is backlighted by a single-colorLED that is normally inactive, but turns on when in DND or Hold mode. Itmay be useful to distinguish between the two modes by having the LEDblink while in DND mode, and continuously illuminated while a call is onhold, for example.

The input device 74 in these embodiments is a group of three smallmomentary push buttons is situated along one edge of the badge tofacilitate volume adjustment during calls, and manipulation of thedisplay menus when no call is in progress. The top and bottom buttons ofthe group increase and decrease call loudness, respectively, when a callis in progress. When the badge is inactive, they act as scroll controlsfor manipulating menus and text on the display. The middle button isused to make menu selections in this context.

The status indicator 78 in these embodiments is an LED display which iscapable of displaying two colors is used to signal operational status.For example, a fast blinking green indicates that a message is waiting.Other blinking patterns (such as blinking red) may be used to indicateother conditions, such as hand-off in progress or low battery. Theheadset jack 80 is provided to enable one to plug in an externalmicrophone/earphone combination. Use of the jack inhibits the operationof the built-in microphone and/or speaker.

FIG. 4Z is an access device having a badge application for use with thevoice-controlled wireless communications system. The combination of theaccess device with the badge application operates as the badge 32described above. The access device may be a processing unit based devicehaving a microphone and speaker (not shown) that may be a phone, acellular phone, a mobile phone, a Smart phone, a Blackberry-type devicewith a built-in communications capability, a Palm operating system baseddevice with a communications capability, a Windows CE-based device witha communications capability or any other device that has a speaker, amicrophone and sufficient processing power, memory and connectivity toexecute the badge application. The access device may also have thedisplay device 66 that may be used to display a series of user interfacescreens of the badge application along with the soft buttons of thebadge application and the processing unit 58 that executes the badgeapplication. The access device may also include the communications unit50 described above and a memory 59, such as dynamic RAM, static RAM,flash memory, etc., that stores one or more pieces of software/modulesexecuted by the processing unit. For example, when the badge applicationis being used to access the voice-controlled system, the memory maystore an operating system 59 a that controls the overall operation ofthe access device, a transmission application 59 b to control thecommunications functions of the access device and a badge application 59c that implements the functions and operations of the badge devicedescribed above. The access device may also include a power source (notshown) and may include the other elements of the badge described abovethat are not shown or described herein.

FIG. 5 illustrates more details of the voice command interpreter 140that may include a group unit. In a preferred embodiment, the voicecommand interpreter (and each of the elements set forth below) isimplemented in software that has one or more portions of code with eachportion of code having a plurality of lines of computer instructions,although the voice command interpreter may also be implemented inhardware or a combination of hardware and software. The voice commandinterpreter 140 may receive voice commands from a user that are fed intoa speech recognition engine 200 (such as the commercially availableNuance speech recognition engine) and a grammar store 202 that is usedby the speech recognition engine 200 to recognize commands and userwords as is known. The voice command interpreter 140 may also include aresult chooser 204 and a command executor 206 wherein the speechrecognition engine 200 identifies one or more possible words for a voicecommand, the result chooser 204 selects the “best” words that correspondto one or more words of the voice command and the command executor 206executes the command that was chosen by the result chooser 204. Thevoice command interpreter 140 may also include a group unit 208 thatreceives call statistics (as described below), generates group callstatistics and probabilities, generates modified grammar based on theprobabilities and then store modified grammar into the grammarstore/database 202 (as described below) that enables the speechrecognition to better recognize the voice commands (and in particularuser names) by taking advantage of group calling statistics. In oneimplementation, then grammar store/database 202 may be stored in thegrammar database 260 that is part of the system database 130. Now, themethod implemented by the group unit is described in more detailalthough it should be understood that the method shown in FIG. 6 can beimplemented on any system that utilizes a speech recognition system.

FIG. 6 illustrates a method 300 for speech recognition using groupcalling and FIG. 7 illustrates an example of calling statistics 310 thatmay be used by the speech recognition method. In one implementation, themethod process described below may be implemented in software that hasone or more portions of code with each portion of code having aplurality of lines of computer instructions, although the method mayalso be implemented in hardware or a combination of hardware andsoftware. The method may be implemented on a communication system (suchas the speech recognition communication system described above) in whichthe system has one or more groups of user as described below. In themethod, the group unit of the voice command interpreter may receivegroup to group calling data (302) from the speech recognitioncommunication system. The group to group calling data may be gathered bya calling data gathering unit of the group unit and may be implementedin software in one example. In particular, for each call, the groups ofthe calling and called parties are determined and stored and then usedto generate group to group calling statistics.

It has been discovered empirically that hospital calling patternsexhibit the two properties discussed above, locality andsubstitutability. An example of the group to group calling statisticsfor a hospital implementation of the speech recognition communicationsystem is shown in FIG. 7. In the method, a group is one or more usersof the speech recognition communication system who have been groupedtogether due to job functions, geographic location and the like. In ahospital implementation, each group may be a department of the hospital(such as a cancer center, nursing admin., PICU, etc. as shown in FIG.7.) The group to group calling data may be data showing the calls madefrom a first group to other groups in an organization that is using thespeech recognition communication system which results in probabilitiesthat particular groups are called by other groups. For example, in FIG.7, the statistics show calls from an oncologist group (a group ofprofessionals that include the oncology specialists at the hospital) tothe other groups within the hospital. In the method, a call datagathering module of the speech recognition communication system (notshown) may continuously gather the group to group call statistics ascalls are placed.

Group-to-group calling statistics stabilize over a limited period oftime which may be adjusted experimentally, and the system needs to reacha steady state before using the group calling statistics. For example,one may find experimentally that a system reaches a steady state overfive weeks. In this example, the system would accumulate data for fiveweeks before taking advantage of the group calling statistics. To ensurethat the group to group call statistics accurately reflect the currentoperating state of the speech recognition communication system (such aschanges in the groups, changes in the memberships of the groups orchanges in current calling patterns), the earlier group to group callstatistics may be deleted after a predetermined period of time.Furthermore, the group call statistics that are used to calculate theprobabilities are continuously updated (with older call data beingdiscarded and newer call data being used). For example, if one were tofind that the system required five weeks worth of data to reach a steadystate, the oldest data would be aged out and deleted as new data wasadded, thus always maintaining a rolling five week collection.Similarly, older data could be deweighted instead of deleted, to ensurethat current calling patterns were reflected. In the system, a set ofcall statistics for each group to all other groups in the speechrecognition communication system may be gathered (which may be known asa particular group's group to group call statistics) and stored.

The group unit may, based on the group to group call statistics,determine a probability that a user assigned to a particular group willcall a different group (304). A group probability unit of the group unitmay perform this process and the group probability unit may beimplemented in software in one example. Thus, the probabilities thateach user of the particular group will call other groups is determined.A grammar expression based upon these probabilities may then beformulated as follows:

$G = {\bigcup\limits_{i}\left( {\left. G_{{dept}_{i}} \right.\sim P_{i}} \right)}$where

$\bigcup\limits_{i}$is the union over each department dept_(i), dept_(i) represents the ithdepartment,

G_(dept) _(i) is a grammar of terms that lists names in dept_(i);

P_(i) is the probability that a called user is a member of dept_(i);

And G_(dept) _(i) ˜P_(i) gives the grammar expression in which G_(dept)_(i) is weighted by probability P_(i).

For example, where there are four possible called departments, i=4 andthe final grammar is the union of four department grammars, eachweighted by its relative probability as follows:G=(G _(dept) ₁ ˜P ₁)∪(G _(dept) ₂ ˜P ₂)∪(G _(dept) ₃ ˜P ₃)∪(G _(dept) ₄˜P ₄)

The probabilities P_(i) are computed from the stored statistics,modified as time goes on and calls continue to occur.

For users in the Oncology group shown in FIG. 7, the final grammar isthe union of the Cancer Center, Nursing Admin, PICU, and 2100 grammars,each weighted with a probability based on its calling statistics asfollows:G=(G _(cancercenter)˜0.53)∪(G _(NursingAdmin)˜0.40)∪(G _(PICU)˜0.02)∪(G₂₁₀₀˜0.02)

As a result of the modified grammar described above, the speechrecognition system is likely to be able to more accurately (and morequickly) recognize a spoken name by a user since the determinedweightings allow the speech recognition to more accurately predict theuser name. The improvement in speech recognition may show up as areduction in error, an increase in the correct acceptance rates, or acombination of the two.

The system works best when all users are assigned to at least onedepartment. To accommodate the possibility that this may not be thecase, a “catch-all” grammar file is provided for each site, that listsunassigned users.

The above group calling statistics may be adjusted if the particularinstallation of the speech recognition system has a group with a verylarge number of users, but that group is not frequently called. Theissue is that the large group that is not frequently called will resultin users in that group being assigned low probabilities during the groupto group call probabilities. To compensate for this situation, theprobabilities of users in that group are adjusted upwards.

Similarly, if there exists in sufficient calling statistics at any giventime, the probabilities for some departments may be artificially low,and the speech recognition system may inappropriately eliminate namesfrom consideration. To rectify this situation, each department must begiven at least a minimum probability.

As an additional benefit, the above use of the group to group callingstatistics to modify the grammar allows the system to have backoffdialogs to help recover from user error. For example, the followingbackoff dialog allows the system to recover from user who misremembersthe last name of the calling party:

Backoff Dialog

-   -   User: Call Jerry Storm    -   Genie: Sorry, I didn't get that name. Please say the department    -   User: Hardware    -   Genie: OK, now say the first and last name—or just the first        name if that's all you know    -   User: Jerry    -   Genie: Finding Jerry Stark . . .    -   User: Oh, that's his name—couldn't remember it

While the foregoing has been with reference to a particular embodimentof the invention, it will be appreciated by those skilled in the artthat changes in this embodiment may be made without departing from theprinciples and spirit of the disclosure, the scope of which is definedby the appended claims.

The invention claimed is:
 1. A computer implemented speech recognitionsystem, comprising: a communication system having one or more groups ofusers, each group of user having a group to group calling statistic thatis a measure of whether the user of each group calls users of othergroups of the communication system; a speech recognition engine that ispart of the communication system and generates a set of voice commandinterpretations based on a voice command of a user and a set of grammar,the voice command including a name of a person; and the speechrecognition engine further comprises a group unit that adjusts thegrammar used by the speech recognition engine based on group to groupcalling statistics that modify a weighting of the grammar to facilitatethe recognition of a name of a person used in the voice command.
 2. Thesystem of claim 1, wherein the group unit further comprises a call datagathering unit that gathers, for each call, a group to which a callingparty is assigned and a group to which a called party is assigned togenerate the group to group calling statistics for a particular group.3. The system of claim 2, wherein the group unit further comprises agroup probability unit that calculates, for a particular group, aprobability that each other group in the communication system is calledby users of the particular group based on the group to group callingstatistics.
 4. The system of claim 3, wherein the group unit furthercomprises a grammar modifier unit that modifies the grammar expressionsubmitted to the speech recognition engine based on the probability thateach other group in the communication system is called by users of theparticular group.
 5. The system of claim 2, wherein the call datagathering unit continuously gathers, for each call, a group to which acalling party is assigned and a group to which a called party isassigned to generate the group to group calling statistics for aparticular group.
 6. The system of claim 1, wherein the communicationsystem further comprises a controlling computer, one or moreconcentrators connected to the controlling computer by a network, abadge that communicates using a protocol with one of the concentratorsand wherein the controlling computer uses the speech recognition engineto receive a voice command from a particular user through the badge andinterpret the voice command of the user to generate a set of voicecommands interpretations.
 7. The system of claim 1, wherein thecommunication system further comprises a controlling computer, an accessdevice with a badge application that communicates with the controllingcomputer wherein the controlling computer uses the speech recognitionengine to receive a voice command from a particular user through thebadge application and interpret the voice command of the user togenerate a set of voice commands interpretations.
 8. The system of claim1, wherein the one or more groups of users further comprises one or moredepartments in a health care industry.
 9. A computer implemented speechrecognition method in a communication system having one or more groupsof users, each group of user having a group to group calling statisticthat is a measure of whether the user of each group calls users of othergroups of the communication system and wherein the communication systemhas a speech recognition engine that generates a set of voice commandinterpretations based on a voice command of a user and grammar, thevoice command including a name of a person, the method comprising:adjusting, using a group unit of the speech recognition engine, thegrammar used by the speech recognition engine based on group to groupcalling statistics; and modifying, using the group unit of the speechrecognition engine, a weighting of the grammar to facilitate therecognition of a name of a person used in the voice command.
 10. Themethod of claim 9, wherein adjusting the set of grammar furthercomprises gathering, using a call data gathering unit of the speechrecognition engine, for each call, a group to which a calling party isassigned and a group to which a called party is assigned to generate thegroup to group calling statistics for a particular group.
 11. The methodof claim 10, wherein adjusting the set of grammar further comprisescalculating, using a group probability unit of the speech recognitionengine, for a particular group, a probability that each other group inthe communication method is called by users of the particular groupbased on the group to group calling statistics.
 12. The method of claim10, wherein the gathering further comprises continuously gathering, foreach call, a group to which a calling party is assigned and a group towhich a called party is assigned to generate the group to group callingstatistics for a particular group.
 13. The method of claim 9, whereinthe one or more groups of users further comprises one or moredepartments in a health care industry.